570
FXUS65 KBYZ 100109
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
709 PM MDT FRI OCT 9 2026
KEY MESSAGES
- COLD FRONT ARRIVES LATE TONIGHT/EARLY SATURDAY, WITH MUCH COOLER
CONDITIONS THIS WEEKEND THROUGH MONDAY. MANY LOCATIONS COULD
SEE THEIR FIRST FREEZE OF THE SEASON SUNDAY NIGHT OR MONDAY
NIGHT.
- STRONG WEATHER SYSTEM MOVES INTO REGION THIS WEEKEND. SNOW
ACCUMULATION IS LIKELY SATURDAY NIGHT TO MONDAY FOR THE
MOUNTAINS AND FOOTHILLS, WITH RAIN AND SOME WET SNOW AT LOWER
ELEVATIONS. POTENTIAL IMPACTS TO TRAVEL AND OUTDOOR RECREATION.
- WEATHER PATTERN REMAINS UNSETTLED THROUGH MUCH OF NEXT WEEK.
UPDATE
HAVE UPGRADED THE WINTER STORM WATCH FOR THE BEARTOOTH-ABSAROKA
AND CRAZY MOUNTAINS TO A WARNING. HAVE ALSO ISSUED A WINTER STORM
WARNING FOR THE MELVILLE FOOTHILLS AS DEEP E-SE WINDS WILL FAVOR
THE EAST SIDE OF THE CRAZIES. CONFIDENCE IS HIGH FOR MOST OF THE
WESTERN FOOTHILLS TO SEE SOME WET SNOW ACCUMULATION AND HAVE
ISSUED A WINTER WEATHER ADVISORY FOR REMAINING PORTIONS OF
WHEATLAND AND SWEET GRASS COUNTIES, LIVINGSTON AREA AND NORTHERN
PARK COUNTY. TRAVEL ON I-90 AND US-191 THROUGH THESE AREAS WILL BE
DIFFICULT AT TIMES STARTING LATE SATURDAY NIGHT AND CONTINUING
INTO MONDAY.
OTHERWISE THERE REMAINS HIGH UNCERTAINTY WITH REGARD TO SNOW
ACCUMULATIONS AT LOWER ELEVATIONS. GREATEST POTENTIAL REMAINS WEST
OF BILLINGS, WITH A POSSIBLE SURGE OF HEAVIER SNOW/PRECIP AS
MOISTURE FROM REMNANTS OF HURRICANE RACHEL LIFTS THROUGH THE WEST
HALF OF THE CWA SUNDAY NIGHT INTO MONDAY. IF SURFACE COLD AIR
DEEPENS ENOUGH, THIS COULD BE THE BEST OPPORTUNITY FOR HILLS
AROUND BILLINGS TO SEE ACCUMULATING SNOWFALL. STAY TUNED.
JKL
DISCUSSION
NEXT 7 DAYS (THROUGH NEXT THURSDAY)...
SATELLITE IMAGERY SHOWS FLAT RIDGE OVER OUR REGION WHILE STRONG
UPPER TROUGH WAS DIGGING SOUTH THROUGH BRITISH COLUMBIA. IN THE
MEANTIME, FLAT WESTERLY FLOW OVER OUR REGION HAS RESULTED IN A
VERY WARM BREEZY DAY. HUMIDITY READINGS ARE ALREADY IN THE TEENS
IN THE FOOTHILLS AND 20S ACROSS MANY OTHER LOCATIONS IN OUR CWA.
WINDS HAVE BEEN GUSTING TO NEAR 50 MPH FREQUENTLY IN THE FOOTHILLS
NEAR LIVINGSTON AND 15 TO 30 MPH ACROSS OUR WESTERN ZONES. A RED
FLAG WARNING CONTINUES THROUGH 9 PM FOR PORTIONS OF SOUTH CENTRAL
MONTANA AND NORTH CENTRAL AND NORTHEASTERN WYOMING. A FEW RECORD
HIGHS ARE POSSIBLE THIS AFTERNOON AS WELL THANKS TO A PREFRONTAL
WARMING ENVIRONMENT.
FOR TONIGHT, DOWNSLOPE FLOW WILL KEEP IT RELATIVELY MILD MOST OF
THE NIGHT. HOWEVER, A DRY COLD FRONT WILL DROP INTO THE AREA LATE
LEADING TO A SWITCH TO NORTHERLY UPSLOPE WINDS GOING INTO
SATURDAY. THIS WILL START A COOLING TREND THROUGH THE REST OF THE
WEEKEND.
AS THE AFOREMENTIONED UPPER TROUGH DROPS INTO THE PACIFIC NW, WE
WILL SEE AN INCREASING CHANCE OF SHOWERS IN OUR FAR WESTERN ZONES
AS A MOIST SOUTHWEST FLOW DEVELOPS IN THE MID LEVELS OVERRUNNING
OUR NORTHEASTERLY SURFACE FLOW. MODEL TRENDS HAVE KEPT THE MAIN
ENERGY IN THE TROUGH FURTHER WEST AND SOUTH THAN EARLIER RUNS,
DELAYING ATMOSPHERIC COOLING AND THE EFFECTS OF THE RELATED UPPER
DYNAMICS FROM REACHING OUR CWA. HOWEVER, WE ARE CONFIDENT IN
SHOWERS OVER OUR WESTERN ZONES THANKS TO A GOOD MOISTURE FETCH IN
THE MID LEVEL SOUTHWEST FLOW. THERE IS ENOUGH INSTABILITY FOR SOME
GENERAL THUNDER SATURDAY AFTERNOON AS WELL, MAINLY OVER OUR
MOUNTAINS.
THERE DOES REMAINS NOTABLE DISCREPANCY IN THE ENSEMBLES OVER HOW
THIS SYSTEM EVOLVES THROUGH THE WEEKEND AND INTO MONDAY. WHILE THE
MODELS HAVE TRENDED BOUNDARY LAYER TEMPS WARMER OVER THE PLAINS,
THE CHANCE OF SIGNIFICANT SNOWFALL REMAINS FOR THE MOUNTAINS AND
FOOTHILLS DUE TO SIGNIFICANT MOISTURE FETCH (POSSIBLY AIDED BY
THE REMNANTS OF HURRICANE RACHEL). FOR NOW, WE ARE BECOMING MORE
CONFIDENT IN SEEING COLDER AIR MOVE INTO OUR FAR WESTERN ZONES
SATURDAY NIGHT. PRECIPITATION SHOULD CHANGE OVER TO ALL SNOW IN
THE HIGH COUNTRY AND WE MAY SEE A MIX DEVELOP IN THE ADJACENT
FOOTHILLS. THE COLDER AIR GRADUALLY CREEPS EAST SUNDAY INTO SUNDAY
NIGHT WHILE 500 MB HEIGHT FALLS MOVE IN AND MID LEVEL MOISTURE
FLOW ALSO INCREASES (EC EXTREME FORECAST INDEX INDICATES A SHIFT
OF TAILS OVER OUR SOUTHWEST BY SUNDAY). THUS, WE EXPECT THE
HEAVIEST PRECIPITATION/SNOWFALL TO OCCUR LATER SATURDAY NIGHT
THROUGH SUNDAY NIGHT. DUE TO THE SOMEWHAT SLOWER TREND OF EASTWARD
PROGRESSION IN THE MODELS, WE HAVE ALSO EXTENDED THE WINTER STORM
WATCH THROUGH MONDAY MORNING. A MIX OF RAIN AND SNOW IS POSSIBLE
OUT INTO THE PLAINS INCLUDING YELLOWSTONE COUNTY SUNDAY OR SUNDAY
EVENING...THOUGH ACCUMULATIONS WILL BE LIMITED, ESPECIALLY FOR THE
RIVER VALLEYS.
BY MONDAY AFTERNOON, THE UPPER TROUGH WEAKENS AND LINGERS OVER
THE DESERT SOUTHWEST REGION. THE BEST MOISTURE AND ACCOMPANYING
DYNAMICS SHIFT EAST OR ARE CUT OFF FROM OUR AREA AS A SURFACE HIGH
SETTLES OVER OUR CWA. HOWEVER, TROUGHINESS ALOFT MAY STILL RESULT
IN LIGHT POCKETS OF PRECIPITATION OVER THE REGION, BUT WITH LITTLE
ADDITIONAL IMPACT.
BY MIDWEEK, ENSEMBLE ANALYSIS SUGGEST THE WEAKENED UPPER LOW MAY
TRACK TO OUR SOUTH AND SWING MOISTURE AND ASCENT INTO OUR SOUTH
AND EASTERN ZONES WEDNESDAY PRODUCING A GOOD CHANCE OF LOWER
ELEVATION SHOWERS AND MOUNTAIN SNOW SHOWERS. AT THE VERY LEAST,
EXPECT BELOW NORMAL TEMPS AND UNSETTLED CONDITIONS THROUGH
MIDWEEK.
SNOW TOTALS...WHILE SOME UNCERTAINTY IN TIMING REMAINS, WE
CONTINUE TO FEEL CONFIDENT THE BEARTOOTH/ABSAROKA AND CRAZY
RANGES WILL SEE SIGNIFICANT SNOWFALL WITH THIS SYSTEM. (70-80%
CHANCE OF 12+ INCHES ABOVE 8K FT). A WINTER STORM WATCH IS IN
EFFECT FROM SATURDAY NIGHT THROUGH MONDAY MORNING. SNOW
ACCUMULATION ELSEWHERE WILL BE ELEVATION DEPENDENT, ESPECIALLY AS
IT MOVES INTO THE PLAINS. FOR THE FOOTHILLS, SNOW LEVELS FALL TO
UNDER 5K FT LATE SATURDAY NIGHT FROM WHEATLAND TO PARK COUNTIES,
AND FURTHER LOWER SUNDAY. WE HAVE A 60-90% CHANCE OF AT LEAST TWO
INCHES AT LIVINGSTON, HARLOWTON AND BIG TIMBER AND ALSO RED LODGE.
THE HIGHER HILLS SURROUNDING BILLINGS MAY SEE AN INCH OR TWO AS
WELL...THOUGH THE CITY ITSELF MAY STRUGGLE TO ACCUMULATE THE WET
SNOWFALL. HEAVY SNOW IS POSSIBLE ALONG THE MELVILLE FOOTHILLS ON
THE EAST SIDE OF THE CRAZIES, THANKS TO DEEP EASTERLY UPSLOPE FLOW
AND PROXIMITY TO THE BEST MOISTURE FETCH ALOFT. WE MAY EVEN NEED
TO MONITOR THIS AREA FOR A POSSIBLE WINTER STORM WARNING (6+ INS).
FURTHER EAST, INCLUDING SHERIDAN AND THE BIG HORNS REGION, TEMPS
ARE PROGGED TO REMAIN TO WARM FOR MUCH ACCUMULATING SNOWFALL.
OVERALL PRECIPITATION...DUE TO THE SIGNIFICANT MOISTURE FETCH,
OVERALL PRECIP WITH THIS SYSTEM WILL BE WIDESPREAD AND
SIGNIFICANT. ENSEMBLES SHOW TOTALS OF 0.25-0.50" IN THE EAST AND
1-1.5" IN THE WEST. WESTERN MOUNTAINS COULD SEE MORE THAN THIS, AS
COULD LOCALES IN THE EAST, DEPENDING ON THE EXACT TRACK AND
IMPACTS OF RACHEL'S MOISTURE.
IMPACTS...MODERATE TO HEAVY SNOW WOULD AFFECT TRAVEL, OUTDOOR
RECREATION, AND POSSIBLY WEIGH DOWN TREE LIMBS CAUSING TREE
DAMAGE AND LOCAL POWER OUTAGES.
TEMPS...EXPECT HIGHS RANGING FROM 50S WEST TO NEAR 80 IN THE
SOUTHEAST SATURDAY...30S WEST TO AROUND 50 EAST ON SUNDAY AND
MONDAY. READINGS WILL BE IN THE 40S TO 50S TUESDAY AND GRADUALLY
WARM TO UPPER 50S AND LOWER 60S BY THURSDAY. BT
AVIATION
00Z DISCUSSION...GUSTY WINDS WILL CONTINUE OVER THE FOOTHILLS
THIS EVENING INTO TONIGHT. A COLD FRONT PASSAGE TONIGHT INTO
SATURDAY MORNING WILL THEN SWITCH WINDS OUT OF THE NORTH AND EAST
AT THE SURFACE, ENDING THE GUSTY WINDS OVER THE FOOTHILLS. EXPECT
WINDS TO THEN STRENGTHEN OUT OF THE NORTH AND EAST THROUGH THE DAY
SATURDAY. OUTSIDE OF THE WIND, ISOLATED TO SCATTERED RAIN
SHOWERS, AND POSSIBLY WEAK THUNDERSTORMS (LOW CHANCE), ARE
FORECAST SATURDAY. SATURDAY EVENING INTO SATURDAY NIGHT, EXPECT
SHOWER COVERAGE TO INCREASE OVER SOUTH-CENTRAL MONTANA, WITH
PRECIPITATION BECOMING A MIX OF RAIN AND SNOW. LOW CEILINGS ARE
ALSO EXPECTED TO DEVELOP LATE SATURDAY CAUSING WIDESPREAD MVFR TO
IFR CONDITIONS OVER SOUTH- CENTRAL MONTANA. LOCALIZED LIFR
CONDITIONS CAN EVEN BE EXPECTED WHERE HEAVIER SNOW DEVELOPS
SATURDAY NIGHT, MAINLY AROUND KLVM TO K6S0 AND K3HT.
AT KSHR, SMOKE FROM A NEARBY WILDFIRE MAY CAUSE LOCALIZED
VISIBILITY REDUCTION AT TIMES THIS EVENING INTO EARLY SATURDAY. LA
PRELIMINARY POINT TEMP/POPS
SAT SUN MON TUE WED THU FRI
-----------------------------------------------------------
BIL 053/064 035/042 032/045 032/052 037/059 040/058 037/063
02/W 9+/O +7/O 11/B 22/W 32/W 10/U
LVM 048/064 028/041 024/045 025/053 028/056 029/057 028/064
28/T ++/O +7/O 11/B 12/W 31/B 10/U
HDN 048/069 037/047 032/048 031/056 035/061 037/060 032/065
00/B 9+/R +7/O 11/B 34/W 42/W 11/U
MLS 050/069 041/048 036/047 035/056 039/059 041/057 037/060
00/B 79/R +8/R 11/B 34/W 43/W 11/U
4BQ 054/073 043/051 039/050 037/058 041/059 042/056 037/060
00/U 46/R 96/R 21/B 45/W 54/W 21/U
BHK 052/075 037/051 031/047 031/056 035/060 036/056 032/059
00/U 38/R +8/R 12/W 25/W 54/W 21/B
SHR 052/073 035/050 031/049 029/057 033/060 035/058 031/063
02/W 78/R 94/R 22/W 55/W 62/W 21/U
BYZ WATCHES/WARNINGS/ADVISORIES
MT...WINTER WEATHER ADVISORY IN EFFECT FROM MIDNIGHT SATURDAY
NIGHT TO NOON MDT MONDAY FOR ZONES 40-63-65-66-141-228.
WINTER STORM WARNING IN EFFECT FROM 6 PM SATURDAY TO NOON MDT
MONDAY FOR ZONES 67-68.
WINTER STORM WARNING IN EFFECT FROM MIDNIGHT SATURDAY NIGHT
TO NOON MDT MONDAY FOR ZONE 172.
RED FLAG WARNING IN EFFECT UNTIL 9 PM MDT THIS EVENING FOR
ZONES 117-123-124-126.
WY...RED FLAG WARNING IN EFFECT UNTIL 9 PM MDT THIS EVENING FOR
ZONES 274-284.
WEATHER.GOV/BILLINGS
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